The technological advances described above should permit more meaningful studies of subgingival plaque. Studies in the next year will attempt 1) to develop additional liquid media to cultivate organisms which fail to grow in broth, 2) to characterize and develop methods for identification of Gram negative organisms which predominate in subgingival plaque, 3) determine the nature and composition of subgingival plaque in several disease states and in normal plaque. The determination of the range of organisms in subgingival plaque is a necessary prerequisite to studying its development.